doc: man-page for itest

Provide a man-page for the itest command.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

doc/usage/cmd/itest.rst

@@ -0,0 +1,113 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+.. index::
+   single: itest (command)
+
+itest command
+=============
+
+Synopsis
+--------
+
+::
+
+    itest[.b | .w | .l | .q | .s] [*]<value1> <op> [*]<value2>
+
+Description
+-----------
+
+The itest command is used to compare two values. The return value $? is set
+accordingly.
+
+By default it is assumed that the values are 4 byte integers. By appending a
+postfix (.b, .w, .l, .q, .s) the size can be specified:
+
+======= ======================================================
+postfix meaning
+======= ======================================================
+.b      1 byte integer
+.w      2 byte integer
+.l      4 byte integer
+.q      8 byte integer (only available if CONFIG_PHYS_64BIT=y)
+.s      string
+======= ======================================================
+
+value1, value2
+    values to compare. Numeric values are hexadecimal. If '*' is prefixed a
+    hexadecimal address is passed, which points to the value to be compared.
+
+op
+    operator, see table
+
+    ======== ======================
+    operator meaning
+    ======== ======================
+    -lt      less than
+    <        less than
+    -le      less or equal
+    <=       less or equal
+    -eq      equal
+    ==       equal
+    -ne      not equal
+    !=       not equal
+    <>       not equal
+    -ge      greater or equal
+    >=       greater or equal
+    -gt      greater than
+    >        greater than
+    ======== ======================
+
+Examples
+========
+
+The itest command sets the result variable $? to true (0) or false (1):
+
+::
+
+    => itest 3 < 4; echo $?
+    0
+    => itest 3 == 4; echo $?
+    1
+
+This value can be used in the :doc:`if <if>` command:
+
+::
+
+    => if itest 0x3002 < 0x4001; then echo true; else echo false; fi
+    true
+
+Numbers will be truncated according to the postfix before comparing:
+
+::
+
+    => if itest.b 0x3002 < 0x4001; then echo true; else echo false; fi
+    false
+
+Postfix .s causes a string compare. The string '0xa1234' is alphabetically
+smaller than '0xb'.
+
+    => if itest.s 0xa1234 < 0xb; then echo true; else echo false; fi
+    true
+
+A value prefixed by '*' is a pointer to the value in memory.
+
+::
+
+    => mm 0x4000
+    00004000: 00000004 ?
+    00004004: 00000003 ? =>
+    => if itest *0x4000 == 4; then echo true; else echo false; fi
+    true
+    => if itest *0x4004 == 3; then echo true; else echo false; fi
+    true
+
+Configuration
+-------------
+
+The command is only available if CONFIG_CMD_ITEST=y.
+
+Return value
+------------
+
+The return value $? is 0 (true) if the condition is true and 1 (false)
+otherwise.

doc/usage/index.rst

@@ -72,6 +72,7 @@ Shell commands
    cmd/history
    cmd/host
    cmd/if
+   cmd/itest
    cmd/imxtract
    cmd/load
    cmd/loadb